@Override
public boolean onTouchEvent(MotionEvent ev) {
  mLeftDragger.processTouchEvent(ev); 
  mRightDragger.processTouchEvent(ev); 
  final int action = ev.getAction(); boolean wantTouchEvents = true; 
  switch (action & MotionEventCompat.ACTION_MASK) { 
    case MotionEvent.ACTION_DOWN: { 
      final float x = ev.getX(); 
      final float y = ev.getY(); 
      mInitialMotionX = x; 
      mInitialMotionY = y; 
      mDisallowInterceptRequested = false; 
      mChildrenCanceledTouch = false; 
      break; 
    } 
    case MotionEvent.ACTION_UP: { 
      final float x = ev.getX(); 
      final float y = ev.getY(); 
      boolean peekingOnly = true;
      final View touchedView = mLeftDragger.findTopChildUnder((int) x, (int) y); 
      if (touchedView != null && isContentView(touchedView)) { 
        final float dx = x - mInitialMotionX; 
        final float dy = y - mInitialMotionY; 
        final int slop = mLeftDragger.getTouchSlop(); 
        if (dx * dx + dy * dy < slop * slop) { 
          // Taps close a dimmed open drawer but only if it isn't locked open. 
          final View openDrawer = findOpenDrawer(); 
          if (openDrawer != null) { 
            peekingOnly = getDrawerLockMode(openDrawer) == LOCK_MODE_LOCKED_OPEN; 
          } 
        } 
       } 
      closeDrawers(peekingOnly); 
      mDisallowInterceptRequested = false; 
      break; 
    } 
    case MotionEvent.ACTION_CANCEL: { 
      closeDrawers(true); 
      mDisallowInterceptRequested = false;
      mChildrenCanceledTouch = false; break; 
    } 
  } 
  return wantTouchEvents;
}

mDrawerLayout.addDrawerListener(new DrawerLayout.DrawerListener() { 
 @Override 
 public void onDrawerSlide(View drawerView, float slideOffset) {

 }

 @Override 
 public void onDrawerOpened(View drawerView) {
  mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_OPEN);
 }

 @Override public void onDrawerClosed(View drawerView) {
  mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED); 
 }

 @Override public void onDrawerStateChanged(int newState) {

 }
});

/** 
* 监听侧边栏的页面选择。 
*/
public interface OnDrawerPageChangeListener { 
 void onPageSelected(boolean isLast);
}

@Override
public void onPageSelected(boolean isLast) { 
 if (isLast) { 
  mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED);
 } else if (mDrawerLayout.getDrawerLockMode(GravityCompat.START) == DrawerLayout.LOCK_MODE_UNLOCKED) {
  mDrawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_OPEN); 
 }
}

final OnDrawerPageChangeListener drawerPageChangeListener = (OnDrawerPageChangeListener) getActivity();
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { 
 @Override 
 public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

 } 
 @Override 
 public void onPageSelected(int position) { 
  if (position == fragmentList.size() - 1) { 
   drawerPageChangeListener.onPageSelected(true); 
  } else { 
   drawerPageChangeListener.onPageSelected(false); 
  } 
 } 
 @Override 
 public void onPageScrollStateChanged(int state) {

 }
});

// 点击除开侧边栏的区域会收起侧边栏。
mDrawerLayout.setOnTouchListener(new View.OnTouchListener() { 
 @Override 
 public boolean onTouch(View v, MotionEvent event) { 
  switch (event.getAction()) { 
   case MotionEvent.ACTION_DOWN: 
    mDrawerLayout.closeDrawers();
    break;
  } 
  return false; 
 }
});